Mine was Iron Man #109 where he not only met Vanguard for the first time but settled his feud with the Crimson Dynamo(then Dmitri Bukharin). I particularly liked the part where Shellhead and his ally Jack Of Hearts seemingly sacrifice themselves to save Darkstar, Vanguard and the Dynamo, three people that just a few minutes ago they were fighting. Vanguard asks why an American would do so such a thing for a Russian(the Cold War was still on at the time) and the Dynamo pithily replies "perhaps because the title of HERO is separate from one's nationality, my comrade!"
The whole idea of whether or not a hero/heroine can ever be separated from their nationality is central to the books I've written about Bukharin(now known as Airstrike and his colleague Seraph) incidentally; I'm working on one right now!

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"When I was in college, I was belittling the woman who later become my wife for not knowing who Boba Fett was, and she responded by asking me if I knew who the Prime Minister of Israel was. Surprisingly? Not Mon Mothma."-BKV

Iron Man really doesnt have many definitive stories, Demon in a Bottle is one of them.

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"When I was in college, I was belittling the woman who later become my wife for not knowing who Boba Fett was, and she responded by asking me if I knew who the Prime Minister of Israel was. Surprisingly? Not Mon Mothma."-BKV

I don't have a favorite Iron Man "story" but Iron Man definitely plays a crucial part of me even being a comic fan. I was in 4th grade and my comic collecting to that point was limited to the "toy" comics like G.I.Joe and Transformers and maybe Batman or a Superman every now and then,safe stuff,stuff i knew. Then one day,i made the weekly gas station trips with my dad and i wanted a comic,but i had the current Joe and 'formers issues,so not wanting to go home empty handed,i picked up a Iron Man issue.
Didn't know who Iron Man was,vague idea of any superheroes outside of the Big Guns like Spidey or Supes......but this issue was freakin awesome,i don't know the issue number,but it's the last appearance of the silver and red armor. Tony goes up againt this big nuclear powered looking guy and gets his ass kicked and apparently dies at the end of the issue. I actually thought he was dead,and this single issue started the landslide of comic obsession.
Next came X-men Classic,Justice League International,etc,etc.......by the time i got a Daredevil,i was gone. Hooked for life.
What if this was a blah issue,i wouldn't have cared,maybe wouldn't have ever tried another non-GI-joe comic,who knows,maybe later dropped comics completely. Maybe,maybe not. Something in that Iron Man roped me in,i don't even have that issue in a bag. I wanted to keep it honest with its nowhere near-mint conditon. I do miss the red and silver armor though.
I owe one of my life's great joys to Iron Man,that one comic started it all,and i'm lucky i still have it.

I like all the classics like Demon in a Bottle, Armour Wars, The Dragon Seed Saga, they are basically the storylines which Iron Man is known for and defined his character (in my opinion of course). But my all time fave is 'Long Time Gone.'

This story was featured in Volume 3 Issue 46 (ya know that huge 100 page monster thing). When I read the story I walked away from it with a better understanding of what motivates Tony. The story was brilliantly paced and written. He seemed like a genuine hero by the end, coming out of the ordeal with a better understanding of himself and his situation.

I strongly urge people to try and find this story, it is an old one from (probably) the 70's I can't really tell.

I'm rather partial to the second Armor Wars, it was an interesting spin to get the character back to his roots, that is needing the armor again to save his life and maintain control. (That and the art was amazing)